Cutting tools are well known. A conventional cutting tool typically comprises a tool body that is adapted to mate with a cutting machine. The tool body has a working end and one or more pockets in the working end. A conventional pocket ordinarily includes floor and two seating surfaces, which intersect one another at an apex. The pockets are provided for receiving cutting inserts. A retention screw passes through a mounting hole in each insert and is threaded into a threaded hole in the floor of a corresponding pocket.
A conventional threaded hole is generally perpendicular to the floor of the pocket. As a result, the retention screw is vulnerable to a shear force, which renders the retention screw prone to breaking. The perpendicular orientation of the retention screw is also not the most suitable orientation for the screw because the screw, in this orientation, does not direct the insert toward the seating surfaces effectively. It is desirable to provide a seating arrangement that overcomes these deficiencies.
A conventional cutting insert typically has a top rake face, a flank faces, and a cutting edge between the rake and flank faces. An inboard rake face extends radially inward from the flank face of the cutting insert 30. A ramp edge is provided between an inboard flank face and the rake face. The cutting edge is generally parallel to the bottom of the insert. The ramp edge has a negative geometry. The parallel orientation of the cutting edge and the negative geometry of the ramp edge are not the most suitable characteristics for a cutting insert. These characteristics typically require greater force to cut the workpiece, affecting the ramping angle that can be achieved by the cutting insert, and producing an inferior finish. Consequently, greater efforts and extended cutting operations are required. Moreover, additional independent cutting operations are required to achieve a desired finish. To this end, it is desirable to provide an insert that would achieve greater ramping angles, require less force, and achieve a desired finish in fewer cutting operations.
A conventional tool body has radial and axial surfaces adjacent the pockets. These surfaces may engage the workpiece during cutting operations, especially when performing ramping (i.e., the cutting tool moves axially and radially) or helical interpolation (i.e., the cutting tool moves axially and radially in a helical direction) operations. This surface engagement adversely affects the finish produced by the conventional cutting tool. It is desirable to provide a tool body that has sufficient clearance between the radial and axial surfaces and the workpiece during cutting operations to produce a desirable finish and thus reduce or eliminate the need for additional cutting operations.
During a cutting operation, the temperature of the cutting tool is elevated due to the frictional engagement of the cutting tool and the workpiece. A conventional retention screw can bind with the cutting insert due to the elevated temperature of the cutting tool. As a consequence, the retention screw and thus the cutting insert cannot be readily removed. This is a deficiency with a conventional retention screw. What is needed is a retention screw that is less likely to bind with an insert than a conventional retention screw.
Some conventional tool bodies have flutes for evacuating chips from the workpiece during a cutting operation. The flutes are defined by sidewalls, which are cut into the tool body. The flutes typically originate from the cutting insert and extend in an axial direction away from the working end of the tool body. The transition between the cutting insert and the flute is generally discontinuous and thus obstructs the flow of chips through the flute. What is needed is a cutting tool that has a continuous or smooth transition between the insert and the flute and thus effectively discharges chips from the working end of the cutting tool.